These ionospheric data consist of scaling notes, equipment usage logs, and ionospheric
values in the form of daily work sheets, F-Plots, tabulations, and booklets. The station
notes list the equipment used, power settings, frequencies used, equipment problems,
and other information about the equipment. The daily work sheets, commonly referred
to an 7E's, are the paper forms used for recording the scaled values values of the
ionospheric parameters. Tabulations and booklets contain the published values by ionospheric
parameter. If publication errors arise or are suspected, the daily work sheets are
usually consulted, if they are available.These data are available from the National
Geophysical Data Center (NGDC) as electrostatic copies and some as imaged files. Most
of the data are in the form of daily work sheets, tabulations, and booklets. The booklets
and tabulations have each ionospheric parameter listed on one or two pages, depending
upon the format. The daily work sheets have one day (24 hours) of scaled ionospheric
parameters on each sheet.

While every effort has been made to ensure that these data are accurate and reliable
within the limits of the current state of the art, NOAA cannot assume liability for
any damages caused by any errors or omissions in the data, nor as a result of the
failure of the data to function an a particular system. NOAA makes no warranty, expressed
or implied, or does the fact of distribution constitute such a warranty.